Many applications may employ variable displacement pumps to vary a flow rate of a fluid while delivering pressurized fluid. Some variable displacement pumps including but not limited to, axial piston pumps may be expensive and difficult to maintain while operating under contaminated environments in which the fluid may become dirty easily. Another phenomenon observed in such pumps may be fluid cavitation caused by aeration of the fluid.
Many of the foregoing pumps may be characterized by lower tolerances towards cavitation, and/or may be susceptible to contamination of fluid by dirt, particulate matter, or any other impurity. Hence, the performance of these pumps may deteriorate upon prolonged use of the pump in contaminated or aerated environments.
U.S Publication No. 2009/0088280 relates to a variable displacement gear pump device. The variable displacement gear pump provides variable flow while retaining the advantages generally associated with gear pumps, and without diverting pressurized fluid back to the pump inlet. In one embodiment, a gear pump includes a first gear and a second gear forming an external pump, the first gear rotatable about a fixed axis and drivingly engaging the second gear, the second gear rotating about its central axis and selectively movable in an epicyclical relationship with the first gear whereby the discharge of the pump is varied.
The present disclosure is directed to mitigating or eliminating one or more of the drawbacks discussed above.